I would also favour an A600-option.
Think of this: There is no Commodore machine that fits nicely in a backpack except the A600. With the ACA020 and A604n the A600 is the ultimate mobile machine for WHDload and such (except missing the keypad but you can't have it all at the same time I guess).
Even the C64 is a bit too 'long', and the CD32 has no keyboard (and the A4000 keyboards are too long for backpacks, too).
IMHO the A600 *was* the worst Amiga when introduced back then, but now, given the fact that good retro games which are still 'playable' are mainly adventures and classic action games, the A600 is a very nice and space-saving retro device with a keyboard(!). Just IMHO.